Finance guide

Unit Price Shopping Guide Australia

Read shelf labels on a common basis, check promotional conditions and compare what you will actually pay for the quantity you need.

Updated 17 October 2026 • Reviewed by Tools by Layna Editorial Team • General information only

Start with the shelf unit, not the pack price

A $5 pack can cost more per gram than an $8 pack. Unit pricing puts different sizes on one measurement basis. Australian grocery labels use units such as per kilogram, per 100 g, per litre, per 100 mL or per item; the ACCC explains grocery unit pricing.

Read the unit printed beside the price before comparing. A lower number is only cheaper when the measurement basis is the same.

Worked shelf comparison: $8/kg versus 95 cents/100 g

Convert $8 per kilogram to $0.80 per 100 g by dividing by 10. Compare $0.80 with $0.95 on that same 100 g basis. The $8/kg product is cheaper per measured amount.

For packs, divide price by quantity. A $6.50 pack containing 750 g costs $6.50 ÷ 750 × 100 = $0.87 per 100 g, rounded. A $4.40 pack containing 450 g costs $0.98 per 100 g. Compare using the unrounded values, then round for display.

Use the price you qualify for

Single-pack special: use today’s marked price for that pack size.
Multi-buy: divide the required combined checkout price by the combined quantity. If you buy fewer packs, use the actual single-pack price instead.
Member price: count it only if you qualify and intend to use the offer.
Delivery or pickup: compare the total basket charge separately when switching retailers. A delivery fee shared across many items is not automatically the cost of one product.

For example, two 500 g packs for $7 provide 1,000 g at $0.70 per 100 g. One pack at the ordinary $4 price is $0.80 per 100 g; the multi-buy rate does not apply if you only buy one.

Match the product as well as the unit

Count is useful when the items are comparable. Ten large portions and ten small portions are not equal quantities merely because both packs contain ten. Where weight is available, compare that as well as count.

Use drained edible weight when that is the quantity you intend to eat, rather than paying for liquid you discard. For a concentrate, calculate the prepared volume at the stated dilution before comparing with a ready-to-use product. These are separate usable-quantity checks; the calculator cannot infer the yield from the product name.

Put the labels into the calculator

The Unit Price Calculator accepts grams/kilograms, millilitres/litres or item counts. It displays weight per 100 g, volume per 100 mL and count per item. Compare weight with weight or volume with volume; converting a kilogram label does not establish the density needed to compare it with a litre label.

Enter the actual checkout price and pack quantity.
Choose the pack’s input unit.
Enter the second product using the same measurement type.
Read the standardised prices and check that the products meet the same need.

A short shopping check

Before choosing the cheaper unit price, confirm the size, offer conditions, edible or usable quantity and whether you need that much today. This page resolves shelf-label comparisons. For the separate question of how much spoilage a bulk discount can tolerate, use Unit Price vs Bulk Buying.

Shelf unit-price FAQs

Can I compare a per-kilogram price with a per-100 g price?

Yes, after converting. Divide the per-kilogram price by 10 to express it per 100 g, or multiply the per-100 g price by 10 to express it per kilogram.

Does a sale sticker always mean the lower unit price?

No. Compare the current unit prices and the quantity you must buy to qualify. A differently sized or unpromoted pack may still cost less per unit.

Can this compare litres directly with kilograms?

Not without a valid density or an equivalent usable-quantity measure. Keep the comparison within the same measurement type.

Should I buy the largest pack when its unit price is lowest?

Only if its quantity, storage needs and likely use suit your household. The bulk-buying guide shows how waste can erase a lower shelf unit price.